Amorphous Gallium Oxide Based Optoelectronic Synaptic Device With Dual-mode Color Recognition Capability

With the iterative and updated development of science and technology,people’s demand for data information processing is increasing day by day.Since nearly 80%of external information is perceived and resolved by the ocular visual neuromorphic system,the construction of bionic vision system is highly valued in the research work in the field of artificial intelligence such as biomedical imaging and hyperspectral remote sensing technology.The bionic vision system uses the special structure of human retina to perceive and resolve the visible light broadband data.In recent years,brain-like neuromorphic devices are regarded as an important component of bionic vision morphological system and artificial intelligence chip because of their highly parallel processing ability similar to human brain.The artificial visual morphology system constructed by combining electronic synaptic devices and image sensors can realize bionic vision sensing functions,but it still faces problems such as complexity,connection density,energy consumption and running processing speed.The photoelectric synaptic device avoids the above problems and realizes the photosensitive resolution and information storage of visual information on the unit device.However,the photoelectric synaptic devices currently studied have a single response band to light information and weak signal responsiveness and resolution,which is difficult to meet the current bionic vision system’s requirements for processing visual information.Therefore,it is urgent to prepare a high performance photoelectric synaptic device which can realize accurate sensory resolution and information storage function for wide band illumination information.Gallium oxide（Ga₂O3）is a new kind of wide-band gap oxide semiconductor material with a direct band gap of about 4.95e V.It has the advantages of high absorption coefficient,optical stability and simple preparation process.Therefore,it is widely used as the photosensitive functional layer of photodetectors and sensors.Because the film is rich in deep level oxygen vacancy defects,it has a unique photoelectric response to wide band illumination information.Therefore,this material is selected as the photosensitive functional layer of the photoelectric synaptic device in this paper.The planar MSM structure of the photoelectric synaptic device is prepared by RF magnetron sputtering in the anaerobic environment at room temperature.The photoelectric performance and synaptic plasticity were tested under wide band light stimulation,and the intrinsic relationship between the relaxation path of interface carrier and synaptic plasticity behavior was studied and discussed.The specific research results are as follows:（1）a planar MSM structured optosynaptic device was prepared based on a-Ga₂O₃ material.The device has an order of magnitude difference in photocurrent and persistent photoconductance for light information in a wide band range of visible light.The synaptic plasticity in a wide range of light can be tuned by adjusting light parameters such as intensity,pulse width,number of stimuli,and time interval between adjacent pulses.A variety of synaptic plasticity behaviors were successfully simulated.The internal defect states and the dynamic regulation behavior of charge carriers in the photosensitive functional layer before and after illumination are explained in detail.（2）a-Ga₂O₃-based photoelectric synaptic device successfully simulates the learning behavior and memory forgetting behavior in the process of bionic vision imaging under the wide band light stimulation,which intuitively shows that the photoelectric synaptic device has two kinds of time-efficient spectral information extraction and resolution capabilities,and proves that the device has the image preprocessing function and adaptive perception and regulation function of human retina.To realize the persistent storage function of effective visual feature information.Therefore,the photoelectric synaptic devices prepared in this study have the ability to extract and resolve sensory visual information,and have flexible photo controlled tunable synaptic plastic behavior.The circuit complexity of biomimetic vision neuromorphic system is simplified and the recognition accuracy of wide band spectral information is improved.It meets（better meets）the demand of information processing in the field of bionic visual form.It has great development potential in the field of bionic vision morphological system and artificial intelligence,and broadens the road for future research and development in the field of optoelectronics.